Electric circuit breaker



June 17, 1 941. 5- 1 M ]R 2,246,129

ELECTRIC CIRCUIT BREAKER Filed July 17, 1940 45, r I l% 44 r0 INSULATION Inventor:

' Francis E. FairmamJn by JV C Hi5 ttorney.

Patented June 17, 1941 orrics ELECTRIC CIRCUIT BREAKER Francis E. Fail-man, Jr., South Ardmore, Pa., as-

signor to General tion of New York Electric Company, a corpora- Application July 17, 1940, Serial No. 345,970

6 Claims.

My invention relates to electric circuit breakers and more particularly to circuit breakers of the fluid or gas-blast type.

One of the important problems in connection with circuit breakers of the fluid or gas-blast type involves the size of the fluid storage tanks and the amount of fluid or gas which can mechanically be stored to permit repeated operations at rapid intervals Without having to wait for compressors or the like to recharge the storage tanks. Most circuit breakers are designed to open in response to two different controls, one of which causes opening of the circuit breaker when an abnormal current condition exists on the circuit associated therewith, and the other is usually a manual control by means of which the circuit breaker is opened under normal current conditions for conventional switching purposes. It is obvious that a fluid blast of considerably lower intensity is required for arc-extinguishing purposes when the circuit breaker is used to interrupt normal currents than would be required when used to interrupt abnormal currents, such as might exist under fault conditions. In the arrangements disclosed by the prior art, no distinction was made between interrupting the circuit under normal or abnormal conditions so that a considerable amount of fluid was actually wasted and compressors and air storage tanks of larger capacity were necessary particularly in view of the fact that circuit breakers are usually opened a great many more times under normal current conditions than under abnormal current conditions. Accordingly, it would be desirable to provide a fluid-blast circuit breaker which distinguishes between interruptions of normal and ab normal currents.

It is an object of my invention to provide a circuit breaker of the fluid-blast type which distinguishes in its opening operation between normal and abnormal current conditions.

It is another object of my invention to provide a circuit breaker of the fluid-blast type wherein a fluid blast of one intensity is provided when an abnormal current is interrupted and a fluid blast of a different intensity when a normal current is interrupted.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming apart of this specification.

My invention will be better understood from the following description taken in connection with the accompanying drawing in which Fig. 1 is a schematic diagram partly in section of an electric circuit breaker of the fluid-blast type embodying my invention, and Figs. 2 and 3 illustrate certain modifications thereof.

For explanatory purposes, I have illustrated my invention as applied to a circuit breaker of the cross fluid-blast type, such as is disclosed and claimed in the joint application of David C. Prince, William K. Rankin, and Wilfred F. Skeats, Serial No. 303,126, filed November 6, 1939, and assigned to the same assignee as the present application. It will, of course, be understood by those skilled in the art that my invention is equally applicable to other types of circuit breakers which employ a fluid or gas blast for arc-extinguishing purposes.

Referring now to the drawing, I have illustrated my invention as applied to a fluid-blast circuit breaker Illof the cross-blast type comprising a stationary contact II and a movable contact [2 arranged to be operated so as to draw an arc in arc chute l3. The fixed contact I l is connected to the line terminal it while the movable contact I2 is connected to the line terminal i5. Fixed contact H is provided with spring-pressed contact fingers Ha and longer arcing contact fingers I I' while movable contact I2 is provided with an arcing tip I2 so that, when the contacts separate, an arc occurs between arcing tips II and [2. Immediately after separation of the contacts, one terminal of the arc is transferred by a blast of fluid, preferably air, issuing out of conduit it from contact fingers I I to the contact H" which is provided with a tip of arc-resistant metal. The fluid or gas blast from conduit l6 upon opening of the breaker drives the are into the arc chute l3 against the edges of a plurality of partitions I! in the arc chute, which partitions are transverse to the arc gap and the ends of which extend close to the path of movement of the arcing tip l2 of the movable contact I 2. The circuit breaker l6, illustrated by way of example in order to describe my fluid-blast control means, is not my invention but is described and claimed in copending application, Serial No. 303,126, referred to above.

Any suitable means for producing relative movement between the contacts H and 12 of the circuit breaker It may be provided. In Fig. 1, I have disclosed an arrangement in which circuit breaker I5 is automatically operated by fluid pressure. Accordingly, I have shown a cylinder l8 with a piston 19 connected through a rod 20 to operate a lever 2| secured to the shaft 22. The

shaft 22 has attached thereto an arm of insulating material 23 for operating the movable contact l2 of the circuit breaker. Although circuit breaker I is described with respect to controlling the current flowing in a single phase conductor, it will, of course be understood by those skilled in the art that it may just as well control the current in a plurality of phase conductors in which case a plurality of arms 23 would be pro vided for operating the movable contacts I2 for. controlling the various phase conductors. The arm 23 is shown provided with a pin 24 operating the member 25 secured to the outer end of movable contact l2. Member 25 is arranged to slide on a pair of rods 26, only one of which is shown in the drawing since the other is obscured from view thereby. It will be apparent that, when the shaft 22 is rotated in a counterclockwise direction, the arm 23 will move the contact l2 to the open position of the circuit breaker H] and that, when the shaft 22 is rotated in a clockwise direction, the arm 23 will move the contact l2 to the closed position. The member 25 and the rods 26 constitute a kind of cross-head arrangement by which the movable contact I2 is reciprocated. This type of operating mechanism is described in detail in United States Letters Patent 2,218,797, granted October 22, 1940, upon the joint application of Leonard J. Linde and 'Torild Andersen, and assigned to the same assignee as the present application.

In order to operate the circuit breaker H) as well as to supply a blast of fluid through conduit 16 for arc-extinguishing purposes, a source of fluid pressure 21 is provided which is preferably air under pressure. This source ofair under pressure 21 is connected with the respective ends of cylinder It for operating circuit breaker Ill through a four-way control valve 28. This valve is arranged to control the closing of circuit breaker H] by connecting source 21 with the righthand end of cylinder I8 through conduit 29. For opening the circuit breaker, on the other hand, valve 28 isadapted to interconnect the source of fluid under pressure 27 with the left-hand of cylinderlfi through conduit 30. Valve 28 is so constructed as to vent one end of cylinder 58 to atmosphere through conduit 3| whenever the other end H3 is subjected to pressure from source 21. ;A suitable spring means 32 is provided to bias valve 28 to theclosed position shown in Fig.

1. Valve 28 is arranged to be operated for opening circuit breaker ||J by means of an opening solenoid 33 which is energized from a control circuit to be described hereinafter. Similarly, valve 28 is arranged to be operated to control the closing of circuit breaker It by meansof a closing solenoid 34 which may be energized from any suitable control circuit, not shown.

The source of fluid 2'! is also connected to conduit |fi,f-or supplyinga blast of air adjacent contacts-H and 12 of circuit breaker ill for areeXtinguish-ing purposes, through a blast valve '35 anda serially-connected throttle valve 36. Blast valve 35 is normally biased to the closed position by means of spring .31 and is operated by means of a solenoid 38 which is energized at the desired time from thecontrol circuit to be desoribedhereinafter. Throttle valve 36 is schematically illustrated as of the damper type having a vane 54 normally held in the vertical position to provide the maximum opening as shown in Fig. l, by means of spring 139. A solenoid 4B is provided for throttle valve 36 :to cause pivotal movement of vane 54 to decrease the opening and, hence, re-

strict the flow of fluid into conduit l6. Solenoid 40 is energized from the control circuit to be described hereinafter.

In order to provide a fluid blast of relatively high intensity adjacent contacts II and I2 when circuit breaker it opens in response to an abnormal current condition, it is desirable that blast valve 35 be opened while throttle valve 36 remains in the wide open position shown in Fig. 1. Accordingly, I provide relay 4| energized from current transformer 42 connected in series with terminal |5 of circuit breaker I0 so that relay 4| is responsive to abnormal current condition. Upon the occurrence of such abnormal current condition, relay 4| is energized to operate oon-' tactor 43 which connects solenoid 38 across control power source 44. Simultaneous therewith, contactor 43 causes energization of opening solenoid 33 from control power source 44, whereupon relative separation between contacts II and I2 occurs and a blast of fluid of relatively high intensity is introduced adjacent contacts and I2 for arc-extinguishing purposes. For opening circuit breaker it under normal conditions when, for example, it is desirable to perform certain switching operations, I provide, as illustrated in Fig. l, a manually operable two-pole switch 45 causing simultaneous closing of contacts 46 and 41. The closing of contacts 46 causes energization of blast valve solenoid 33 and opening solenoid 33 from control source 44 in the same manner that the closing of contactor 43 causes energization thereof under abnormal current conditions when relay 4| is energized. However, simultaneously with the closing of contacts 46, contacts 47 are closed to energize solenoid 4B of throttle valve 36 from control source 34, which, in turn, causes vane 54 to rotate so as considerably to restrict the opening through throttle valve 3%, thereby greatly decreasing the intensity of the blast of fluid adjacent contacts H and l2.

The operation of the electric circuit breaker described above will be obvious to those skilled in the art in View of the detailed description included above. Under normal current conditions, relay 4| will initiate the opening of circuit breaker ii] as well as open blast valve 35. Since in this case throttle valve 35 remains in the position shown in Fig. l, a fluid blast of relatively high intensity will be provided adjacent contacts and i2 for arc-extinguishing purposes. On the other hand, when circuit breaker M is opened under normal conditions as by operating manualswitch 45, throttle valve solenoid 40 as well as blast valve solenoid 38 and opening valve solenoid 33 will be energized. The operation of throttle valve 36 considerably impedes the flow of fluid from source 21 to conduit it so that a fluid blast of considerably lower intensity will be provided for arc-extinguishing purposes, thereby conserving the fluid stored in source 21.

It will be understood by those skilled in the art that if a fluid Zblast is desired during the closing operation of circuit breaker ill, suitable means for energizing solenoid 38 when closing solenoid 34 is energized may be provided.

Fluid blasts of different intensities when switching under normal or abnormal conditions may be provided by other arrangements than that disclosed in Fig. 1. Accordingly, in Fig. 2, I have shown an arrangement wherein blast valve 35 assumes two different positions, namely, a wide open position for producing a high intensity blast under abnormal current conditions and a partially open position for producing-a lower intensity blast when circuit breaker I is opened under normal current conditions. The corresponding parts of Fig. 2 are designated by the same reference numerals as in Fig. 1. In order to cause blast valve 35 to assume a partly open position, I provide a suitable stop 48 controlled by solenoid 49 which, when the latter is energized, limits the upward movement of the plunger of solenoid 38, thereby causing blast valve 35 to assume a partly open position to decrease the fluid flow therethrough and, accordingly, limit the intensity of the fluid blast adjacent the separating contacts. Solenoid 49 is preferably energized in the same manner as solenoid 40 of Fig. 1. A suitable spring 50 is provided normally to hold stop 48 in a position which will not interfere with the opening of blast valve 35.

In Fig. 3 I have shown another modification of my invention wherein the corresponding parts are designated by the same reference numerals as in Fig. 1. As in Fig. 1, a blast valve 35 is provided through which a relatively high intensity fluid blast may flow to extinguish the are when the circuit breaker is interrupted under abnormal current conditions. In order to provide a lower intensity fluid blast when the circuit breaker is opened under normal current condi tions, I provide a second fluid-blast valve 5| connected in parallel with blast valve 35 and arranged to allow a lower intensity fluid blast to be introduced adjacent contacts H and I2. Small blast valve 5| is normally held in the closed position by means of spring 52. A solenoid 53 is provided for causing opening thereof. The control circuit for Fig. 3, not shown, will be somewhat diflerent than that shown in Fig. 1 since solenoids 38 and 53 are never simultaneously energized. However, as will be understood by those skilled in the art, any suitable control means may be provided whereby blast valve 35 is opened when the circuit breaker interrupts an abnormal current while blast valve 5| is opened when normal currents are interrupted.

While I have shown and described particular embodiments of my invention as applied to an electric circuit breaker of the fluid-blast type, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from my invention in its broader aspects and I therefore aim in the appended claims to cover all such changes and modifications as fall Within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an electric circuit breaker of the fluidblast type, a pair of relatively movable contacts separable to draw an arc therebetween, a source of fluid under pressure, means for introducing a blast of fluid from said source adjacent said relatively movable contacts for arc-extinguishing purposes, and means for controlling said fluid so as to provide a fluid blast of one initial intensity adjacent said contacts when said circuit breaker is opened under abnormal current conditions and a fluid blast of a different initial intensity when said circuit breaker is opened under normal current conditions.

2. In an electric circuit breaker of the fluid blast type, an arc-confining structure, a pair of relatively movable contacts mounted in said structure and separable to draw an are therebetween, a source of fluid under pressure, means for introducing a blast of fluid from said source into said structure adjacent said relatively movable contacts for arc-extinguishing purposes, and means for varying the initial intensity of said fluid blast in dependence upon whether said circuit breaker is opened on normal or abnormal current conditions.

3. In an electric circuit breaker of the gasblast type, a pair of relatively movable contacts separable to draw an arc therebetween, a source of gas under pressure, means for introducing a blast of gas from said source adjacent said relatively movable contacts for arc-extinguishing purposes, and means for controlling the flow of said gas so as to provide a gas blast of relatively great initial intensity when said circuit breaker is opened under abnormal current conditions and a gas blast of lower initial intensity when said circuit breaker is opened under normal current conditions.

4. In an electric circuit breaker of the fluidblast type, a pair of relatively movable contacts separable to draw an arc therebetween, a source of fluid under pressure, a blast valve for controlling the introduction of a blast of fluid from said source adjacent said relatively movable contacts for arc-extinguishing purposes, a throttle valve connected in series with said blast valve, and means for controlling said throttle valve so as to provide a fluid blast of relatively great intensity when said circuit breaker is opened under abnormal current conditions and a fluid blast of lower intensity when said circuit breaker is operated to the open position by manual control means.

5. In an electric circuit breaker of the fluidblast type, a pair of relatively movable contacts separable to draw an arc therebetween, a source of fluid under pressure, a blast valve for controlling the introduction of a blast of fluid of relatively great intensity adjacent said relatively movable contacts for extinguishing said are when said circuit breaker is opened under abnormal current conditions, and means for limiting the opening movement of said blast valve when said circuit breaker is opened under normal current conditions so as to provide a fluid blast of lower intensity.

6. In an electric circuit breaker of the fluid blast type, a pair of relatively movable contacts separable to draw an arc therebetween, a source of fluid under pressure, means including a first blast valve for controlling the introduction of a blast of fluid from said source of relatively great initial intensity adjacent said relatively movable contacts for extinguishing said are when said circuit breaker is opened under abnormal current conditions, and a second blast valve for controlling the introduction of a blast of fluid from said source of lower initial intensity for extinguishing said are when said circuit breaker is opened under normal current conditions.

FRANCIS E. FAIRMAN, JR.

I I CERTIFICATE OF coRREcTIbN. Patent No. 2,2h,129.' June 1?, 19m.

FRANCIS E. FAIRMAN, JR.

It is hereby certified that error appears in the printed specification oifthe above numbered patentrequiring correction as follows: Page 2, sec- 0nd column, line 15, for the word "normal" read abnormal; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office Signed and sealed this 5th day of August, A. D. 191 1 Henry Van Arsdale,

(Seal) 1 v Acting Commissioner of Patents.

e a I I CERTIFICATE CF CORRECTION. Patent No. 2,2L e,129. June 17, 191 1.

7 FRANCIS ,FAIRMAN, JR.

' It is hereby certified that error appears in the printed specification ofthe above numbered patent-requiring correction as follows Page 2, second column, line for the word- "normal" read --abnormal--; and that the said Letters Patent should be read with this correction thereinthat the same may conform to the record of the case in the Patent Office Signed and sealed this 5th day of August, A. D. 19141 g I I Q Henry Van Arsdale,

(Seal) Acting Commissioner of Patents. 

